From 7dfb38b859531b5cfde6cccd34f897360f785527 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Sun, 2 Jan 2022 13:01:20 +0000
Subject: [PATCH 01/21] Lowercase distribution name in wheel filename and
 .dist-info folder name

---
 flit_core/flit_core/common.py            | 2 +-
 tests/samples/altdistname/pyproject.toml | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/flit_core/flit_core/common.py b/flit_core/flit_core/common.py
index f1f378f5..dd009f52 100644
--- a/flit_core/flit_core/common.py
+++ b/flit_core/flit_core/common.py
@@ -407,7 +407,7 @@ def normalize_dist_name(name: str, version: str) -> str:
 
     See https://packaging.python.org/specifications/binary-distribution-format/#escaping-and-unicode
     """
-    normalized_name = re.sub(r'[-_.]+', '_', name, flags=re.UNICODE)
+    normalized_name = re.sub(r'[-_.]+', '_', name, flags=re.UNICODE).lower()
     assert check_version(version) == version
     assert '-' not in version, 'Normalized versions can’t have dashes'
     return '{}-{}'.format(normalized_name, version)
diff --git a/tests/samples/altdistname/pyproject.toml b/tests/samples/altdistname/pyproject.toml
index 00caf94c..c2d08cad 100644
--- a/tests/samples/altdistname/pyproject.toml
+++ b/tests/samples/altdistname/pyproject.toml
@@ -7,5 +7,5 @@ module = "package1"
 author = "Sir Robin"
 author-email = "robin@camelot.uk"
 home-page = "http://github.com/sirrobin/package1"
-dist-name = "package-dist1"
+dist-name = "package-Dist1"
 

From 291e928c264c611c399116e878179cac352f8667 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Sun, 2 Jan 2022 13:31:35 +0000
Subject: [PATCH 02/21] Use newer importlib APIs when loading module for
 docstring & __version__

---
 flit_core/flit_core/common.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/flit_core/flit_core/common.py b/flit_core/flit_core/common.py
index f1f378f5..6d1a64ff 100644
--- a/flit_core/flit_core/common.py
+++ b/flit_core/flit_core/common.py
@@ -163,10 +163,13 @@ def get_docstring_and_version_via_import(target):
     _import_i += 1
 
     log.debug("Loading module %s", target.file)
-    from importlib.machinery import SourceFileLoader
-    sl = SourceFileLoader('flit_core.dummy.import%d' % _import_i, str(target.file))
+    from importlib.util import spec_from_file_location, module_from_spec
+    mod_name = 'flit_core.dummy.import%d' % _import_i
+    spec = spec_from_file_location(mod_name, target.file)
     with _module_load_ctx():
-        m = sl.load_module()
+        m = module_from_spec(spec)
+        spec.loader.exec_module(m)
+
     docstring = m.__dict__.get('__doc__', None)
     version = m.__dict__.get('__version__', None)
     return docstring, version

From 811d9099a440da93ffa2c003861775b0178e4086 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Sun, 2 Jan 2022 15:20:41 +0000
Subject: [PATCH 03/21] CI: Add Python 3.10, move Windows tests to GH actions
 (#500)

---
 .github/workflows/test.yml |  5 +++--
 appveyor.yml               | 16 ----------------
 tests/test_install.py      |  2 ++
 tox.ini                    |  3 ++-
 4 files changed, 7 insertions(+), 19 deletions(-)
 delete mode 100644 appveyor.yml

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 565a68ce..16e902a1 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -4,10 +4,11 @@ on: [push, pull_request]
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.platform }}
     strategy:
       matrix:
-        python-version: [ 3.6, 3.7, 3.8, 3.9, ]
+        platform: ["ubuntu-latest", "windows-latest"]
+        python-version: [ "3.6", "3.7", "3.8", "3.9", "3.10" ]
     steps:
       - uses: actions/checkout@v2
 
diff --git a/appveyor.yml b/appveyor.yml
deleted file mode 100644
index 08ef1a6c..00000000
--- a/appveyor.yml
+++ /dev/null
@@ -1,16 +0,0 @@
-environment:
-  matrix:
-    - TOXENV: "py37"
-      TOX_APPVEYOR_X64: "1"
-    - TOXENV: "py36"
-      TOX_APPVEYOR_X64: "0"
-
-# The Python version here doesn't matter (except that the commands have the same),
-# as Tox will set up an environment using the Python specified above.
-install:
-  - py -3.7 -m pip install tox tox-appveyor
-
-test_script:
-  - py -3.7 -m tox
-
-build: off
diff --git a/tests/test_install.py b/tests/test_install.py
index 77a90076..94ad3825 100644
--- a/tests/test_install.py
+++ b/tests/test_install.py
@@ -167,6 +167,8 @@ def test_symlink_module_pep621(self):
         )
 
     def test_symlink_module_in_src(self):
+        if os.name == 'nt':
+            raise SkipTest("symlink")
         oldcwd = os.getcwd()
         os.chdir(samples_dir / 'packageinsrc')
         try:
diff --git a/tox.ini b/tox.ini
index 71bc8867..e1689d66 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py{39,38,37,36},bootstrap
+envlist = py{310,39,38,37,36},bootstrap
 skip_missing_interpreters = true
 
 [gh-actions]
@@ -8,6 +8,7 @@ python =
     3.7: py37
     3.8: py38, bootstrap
     3.9: py39
+    3.10: py310
 
 [testenv]
 deps =

From d1e50e6381a8ac0990fe46f3c74e710c3b14f93c Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Mon, 3 Jan 2022 11:23:10 +0000
Subject: [PATCH 04/21] Help for --setup-py: don't say it's the default

---
 flit/__init__.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/flit/__init__.py b/flit/__init__.py
index 8af9b34b..57f689ea 100644
--- a/flit/__init__.py
+++ b/flit/__init__.py
@@ -82,12 +82,11 @@ def main(argv=None):
     parser_build.add_argument('--setup-py', action='store_true',
         help=("Generate a setup.py file in the sdist. "
               "The sdist will work with older tools that predate PEP 517. "
-              "This is the default for now, but will change in a future version."
               )
     )
 
     parser_build.add_argument('--no-setup-py', action='store_true',
-        help=("Don't generate a setup.py file in the sdist. "
+        help=("Don't generate a setup.py file in the sdist. This is the default. "
               "The sdist will only work with tools that support PEP 517, "
               "but the wheel will still be usable by any compatible tool."
              )

From c404ea36f883ba6101581d943844d2986ec2bf28 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Sat, 15 Jan 2022 15:20:39 +0000
Subject: [PATCH 05/21] Add support for external data directory

---
 flit/install.py               | 13 +++++++++++++
 flit_core/flit_core/common.py | 17 +++++++++++++++++
 flit_core/flit_core/config.py | 26 ++++++++++++++++++++++++--
 flit_core/flit_core/sdist.py  |  9 ++++++---
 flit_core/flit_core/wheel.py  | 19 ++++++++++++++++---
 5 files changed, 76 insertions(+), 8 deletions(-)

diff --git a/flit/install.py b/flit/install.py
index fe095d65..3ea9a4bf 100644
--- a/flit/install.py
+++ b/flit/install.py
@@ -196,6 +196,17 @@ def install_scripts(self, script_defs, scripts_dir):
 
                 self.installed_files.append(cmd_file)
 
+    def install_data_dir(self, target_data_dir):
+        for src_path in common.walk_data_dir(self.ini_info.data_directory):
+            rel_path = os.path.relpath(src_path, self.ini_info.data_directory)
+            dst_path = os.path.join(target_data_dir, rel_path)
+            os.makedirs(os.path.dirname(dst_path), exist_ok=True)
+            if self.symlink:
+                os.symlink(os.path.realpath(src_path), dst_path)
+            else:
+                shutil.copy2(src_path, dst_path)
+            self.installed_files.append(dst_path)
+
     def _record_installed_directory(self, path):
         for dirpath, dirnames, files in os.walk(path):
             for f in files:
@@ -332,6 +343,8 @@ def install_directly(self):
         scripts = self.ini_info.entrypoints.get('console_scripts', {})
         self.install_scripts(scripts, dirs['scripts'])
 
+        self.install_data_dir(dirs['data'])
+
         self.write_dist_info(dirs['purelib'])
 
     def install_with_pip(self):
diff --git a/flit_core/flit_core/common.py b/flit_core/flit_core/common.py
index f1f378f5..039d903f 100644
--- a/flit_core/flit_core/common.py
+++ b/flit_core/flit_core/common.py
@@ -416,3 +416,20 @@ def normalize_dist_name(name: str, version: str) -> str:
 def dist_info_name(distribution, version):
     """Get the correct name of the .dist-info folder"""
     return normalize_dist_name(distribution, version) + '.dist-info'
+
+
+def walk_data_dir(data_directory):
+    """Iterate over the files in the given data directory.
+
+    Yields absolute paths - caller may want to make them relative.
+    Excludes any __pycache__ subdirectories.
+    """
+    if data_directory is None:
+        return
+
+    for dirpath, dirs, files in os.walk(data_directory):
+        for file in sorted(files):
+            full_path = os.path.join(dirpath, file)
+            yield full_path
+
+        dirs[:] = [d for d in sorted(dirs) if d != '__pycache__']
diff --git a/flit_core/flit_core/config.py b/flit_core/flit_core/config.py
index b0b6ddbd..ade14b8d 100644
--- a/flit_core/flit_core/config.py
+++ b/flit_core/flit_core/config.py
@@ -120,7 +120,7 @@ def prep_toml_config(d, path):
         )
 
     unknown_sections = set(dtool) - {
-        'metadata', 'module', 'scripts', 'entrypoints', 'sdist'
+        'metadata', 'module', 'scripts', 'entrypoints', 'sdist', 'external-data'
     }
     unknown_sections = [s for s in unknown_sections if not s.lower().startswith('x-')]
     if unknown_sections:
@@ -142,6 +142,27 @@ def prep_toml_config(d, path):
             dtool['sdist'].get('exclude', []), 'exclude'
         )
 
+    data_dir = dtool.get('external-data', {}).get('directory', None)
+    if data_dir is not None:
+        toml_key = "tool.flit.external-data.directory"
+        if not isinstance(data_dir, str):
+            raise ConfigError(f"{toml_key} must be a string")
+
+        normp = osp.normpath(data_dir)
+        if osp.isabs(normp):
+            raise ConfigError(f"{toml_key} cannot be an absolute path")
+        if normp.startswith('..' + os.sep):
+            raise ConfigError(
+                f"{toml_key} cannot point outside the directory containing pyproject.toml"
+            )
+        if normp == '.':
+            raise ConfigError(
+                f"{toml_key} cannot refer to the directory containing pyproject.toml"
+            )
+        loaded_cfg.data_directory = path.parent / data_dir
+        if not loaded_cfg.data_directory.is_dir():
+            raise ConfigError(f"{toml_key} must refer to a directory")
+
     return loaded_cfg
 
 def flatten_entrypoints(ep):
@@ -207,7 +228,7 @@ def _check_glob_patterns(pats, clude):
             raise ConfigError(
                 '{} pattern {!r} is an absolute path'.format(clude, p)
             )
-        if osp.normpath(p).startswith('..' + os.sep):
+        if normp.startswith('..' + os.sep):
             raise ConfigError(
                 '{} pattern {!r} points out of the directory containing pyproject.toml'
                 .format(clude, p)
@@ -227,6 +248,7 @@ def __init__(self):
         self.sdist_include_patterns = []
         self.sdist_exclude_patterns = []
         self.dynamic_metadata = []
+        self.data_directory = None
 
     def add_scripts(self, scripts_dict):
         if scripts_dict:
diff --git a/flit_core/flit_core/sdist.py b/flit_core/flit_core/sdist.py
index 80ccf25d..cb72ea1d 100644
--- a/flit_core/flit_core/sdist.py
+++ b/flit_core/flit_core/sdist.py
@@ -72,13 +72,14 @@ class SdistBuilder:
     which is what should normally be published to PyPI.
     """
     def __init__(self, module, metadata, cfgdir, reqs_by_extra, entrypoints,
-                 extra_files, include_patterns=(), exclude_patterns=()):
+                 extra_files, data_directory, include_patterns=(), exclude_patterns=()):
         self.module = module
         self.metadata = metadata
         self.cfgdir = cfgdir
         self.reqs_by_extra = reqs_by_extra
         self.entrypoints = entrypoints
         self.extra_files = extra_files
+        self.data_directory = data_directory
         self.includes = FilePatterns(include_patterns, str(cfgdir))
         self.excludes = FilePatterns(exclude_patterns, str(cfgdir))
 
@@ -93,8 +94,8 @@ def from_ini_path(cls, ini_path: Path):
         extra_files = [ini_path.name] + ini_info.referenced_files
         return cls(
             module, metadata, srcdir, ini_info.reqs_by_extra,
-            ini_info.entrypoints, extra_files, ini_info.sdist_include_patterns,
-            ini_info.sdist_exclude_patterns,
+            ini_info.entrypoints, extra_files, ini_info.data_directory,
+            ini_info.sdist_include_patterns, ini_info.sdist_exclude_patterns,
         )
 
     def prep_entry_points(self):
@@ -115,6 +116,8 @@ def select_files(self):
         cfgdir_s = str(self.cfgdir)
         return [
             osp.relpath(p, cfgdir_s) for p in self.module.iter_files()
+        ] + [
+            osp.relpath(p, cfgdir_s) for p in common.walk_data_dir(self.data_directory)
         ] + self.extra_files
 
     def apply_includes_excludes(self, files):
diff --git a/flit_core/flit_core/wheel.py b/flit_core/flit_core/wheel.py
index 8c87451e..d921f7cc 100644
--- a/flit_core/flit_core/wheel.py
+++ b/flit_core/flit_core/wheel.py
@@ -57,13 +57,16 @@ def zip_timestamp_from_env() -> Optional[tuple]:
 
 
 class WheelBuilder:
-    def __init__(self, directory, module, metadata, entrypoints, target_fp):
+    def __init__(
+            self, directory, module, metadata, entrypoints, target_fp, data_directory
+    ):
         """Build a wheel from a module/package
         """
         self.directory = directory
         self.module = module
         self.metadata = metadata
         self.entrypoints = entrypoints
+        self.data_directory = data_directory
 
         self.records = []
         self.source_time_stamp = zip_timestamp_from_env()
@@ -74,14 +77,15 @@ def __init__(self, directory, module, metadata, entrypoints, target_fp):
 
     @classmethod
     def from_ini_path(cls, ini_path, target_fp):
-        # Local import so bootstrapping doesn't try to load toml
         from .config import read_flit_config
         directory = ini_path.parent
         ini_info = read_flit_config(ini_path)
         entrypoints = ini_info.entrypoints
         module = common.Module(ini_info.module, directory)
         metadata = common.make_metadata(module, ini_info)
-        return cls(directory, module, metadata, entrypoints, target_fp)
+        return cls(
+            directory, module, metadata, entrypoints, target_fp, ini_info.data_directory
+        )
 
     @property
     def dist_info(self):
@@ -160,6 +164,14 @@ def add_pth(self):
         with self._write_to_zip(self.module.name + ".pth") as f:
             f.write(str(self.module.source_dir.resolve()))
 
+    def add_data_directory(self):
+        dir_in_whl = '{}.data/data/'.format(
+            common.normalize_dist_name(self.metadata.name, self.metadata.version)
+        )
+        for full_path in common.walk_data_dir(self.data_directory):
+            rel_path = os.path.relpath(full_path, self.data_directory)
+            self._add_file(full_path, dir_in_whl + rel_path)
+
     def write_metadata(self):
         log.info('Writing metadata files')
 
@@ -193,6 +205,7 @@ def build(self, editable=False):
                 self.add_pth()
             else:
                 self.copy_module()
+            self.add_data_directory()
             self.write_metadata()
             self.write_record()
         finally:

From 6215968310216bc311b53943bbe3ece3f3254069 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Sat, 15 Jan 2022 15:21:33 +0000
Subject: [PATCH 06/21] Tests for external data directory

---
 .../tests/samples/with_data_dir/LICENSE       |  1 +
 .../tests/samples/with_data_dir/README.rst    |  1 +
 .../with_data_dir/data/share/man/man1/foo.1   |  1 +
 .../tests/samples/with_data_dir/module1.py    |  3 ++
 .../samples/with_data_dir/pyproject.toml      | 26 ++++++++++++++++
 flit_core/flit_core/tests/test_sdist.py       |  9 ++++++
 flit_core/flit_core/tests/test_wheel.py       |  7 +++++
 tests/test_install.py                         | 31 ++++++++++++++++---
 8 files changed, 74 insertions(+), 5 deletions(-)
 create mode 100644 flit_core/flit_core/tests/samples/with_data_dir/LICENSE
 create mode 100644 flit_core/flit_core/tests/samples/with_data_dir/README.rst
 create mode 100644 flit_core/flit_core/tests/samples/with_data_dir/data/share/man/man1/foo.1
 create mode 100644 flit_core/flit_core/tests/samples/with_data_dir/module1.py
 create mode 100644 flit_core/flit_core/tests/samples/with_data_dir/pyproject.toml

diff --git a/flit_core/flit_core/tests/samples/with_data_dir/LICENSE b/flit_core/flit_core/tests/samples/with_data_dir/LICENSE
new file mode 100644
index 00000000..7f5c1948
--- /dev/null
+++ b/flit_core/flit_core/tests/samples/with_data_dir/LICENSE
@@ -0,0 +1 @@
+This file should be added to wheels
diff --git a/flit_core/flit_core/tests/samples/with_data_dir/README.rst b/flit_core/flit_core/tests/samples/with_data_dir/README.rst
new file mode 100644
index 00000000..ef7b7c19
--- /dev/null
+++ b/flit_core/flit_core/tests/samples/with_data_dir/README.rst
@@ -0,0 +1 @@
+This contains a nön-ascii character
diff --git a/flit_core/flit_core/tests/samples/with_data_dir/data/share/man/man1/foo.1 b/flit_core/flit_core/tests/samples/with_data_dir/data/share/man/man1/foo.1
new file mode 100644
index 00000000..c12128d8
--- /dev/null
+++ b/flit_core/flit_core/tests/samples/with_data_dir/data/share/man/man1/foo.1
@@ -0,0 +1 @@
+Example data file
diff --git a/flit_core/flit_core/tests/samples/with_data_dir/module1.py b/flit_core/flit_core/tests/samples/with_data_dir/module1.py
new file mode 100644
index 00000000..87f0370d
--- /dev/null
+++ b/flit_core/flit_core/tests/samples/with_data_dir/module1.py
@@ -0,0 +1,3 @@
+"""Example module"""
+
+__version__ = '0.1'
diff --git a/flit_core/flit_core/tests/samples/with_data_dir/pyproject.toml b/flit_core/flit_core/tests/samples/with_data_dir/pyproject.toml
new file mode 100644
index 00000000..84d165e3
--- /dev/null
+++ b/flit_core/flit_core/tests/samples/with_data_dir/pyproject.toml
@@ -0,0 +1,26 @@
+[build-system]
+requires = ["flit_core >=3.2,<4"]
+build-backend = "flit_core.buildapi"
+
+[project]
+name = "module1"
+authors = [
+    {name = "Sir Röbin", email = "robin@camelot.uk"}
+]
+readme = "README.rst"
+license = {file = "LICENSE"}
+requires-python = ">=3.7"
+dependencies = [
+    "requests >= 2.18",
+    "docutils",
+]
+dynamic = [
+    "version",
+    "description",
+]
+
+[project.scripts]
+foo = "module1:main"
+
+[tool.flit.external-data]
+directory = "data"
diff --git a/flit_core/flit_core/tests/test_sdist.py b/flit_core/flit_core/tests/test_sdist.py
index ca29c4e9..a513758e 100644
--- a/flit_core/flit_core/tests/test_sdist.py
+++ b/flit_core/flit_core/tests/test_sdist.py
@@ -49,3 +49,12 @@ def test_include_exclude():
     assert osp.join('doc', 'test.rst') in files
     assert osp.join('doc', 'test.txt') not in files
     assert osp.join('doc', 'subdir', 'test.txt') in files
+
+
+def test_data_dir():
+    builder = sdist.SdistBuilder.from_ini_path(
+        samples_dir / 'with_data_dir' / 'pyproject.toml'
+    )
+    files = builder.apply_includes_excludes(builder.select_files())
+
+    assert osp.join('data', 'share', 'man', 'man1', 'foo.1') in files
diff --git a/flit_core/flit_core/tests/test_wheel.py b/flit_core/flit_core/tests/test_wheel.py
index 9bb38fb2..51d6def7 100644
--- a/flit_core/flit_core/tests/test_wheel.py
+++ b/flit_core/flit_core/tests/test_wheel.py
@@ -29,3 +29,10 @@ def test_zero_timestamp(tmp_path, monkeypatch):
     # Minimum value for zip timestamps is 1980-1-1
     with ZipFile(info.file, 'r') as zf:
         assert zf.getinfo('module1a.py').date_time == (1980, 1, 1, 0, 0, 0)
+
+
+def test_data_dir(tmp_path):
+    info = make_wheel_in(samples_dir / 'with_data_dir' / 'pyproject.toml', tmp_path)
+    assert_isfile(info.file)
+    with ZipFile(info.file, 'r') as zf:
+        assert 'module1-0.1.data/data/share/man/man1/foo.1' in zf.namelist()
diff --git a/tests/test_install.py b/tests/test_install.py
index 94ad3825..70007e85 100644
--- a/tests/test_install.py
+++ b/tests/test_install.py
@@ -21,11 +21,13 @@
 class InstallTests(TestCase):
     def setUp(self):
         td = tempfile.TemporaryDirectory()
-        scripts_dir = os.path.join(td.name, 'scripts')
-        purelib_dir = os.path.join(td.name, 'site-packages')
         self.addCleanup(td.cleanup)
         self.get_dirs_patch = patch('flit.install.get_dirs',
-                return_value={'scripts': scripts_dir, 'purelib': purelib_dir})
+                return_value={
+                    'scripts': os.path.join(td.name, 'scripts'),
+                    'purelib': os.path.join(td.name, 'site-packages'),
+                    'data': os.path.join(td.name, 'data'),
+                })
         self.get_dirs_patch.start()
         self.tmpdir = pathlib.Path(td.name)
 
@@ -246,11 +248,13 @@ def test_symlink_other_python(self):
         # Called by Installer._get_dirs() :
         script2 = ("#!{python}\n"
                    "import json, sys\n"
-                   "json.dump({{'purelib': {purelib!r}, 'scripts': {scripts!r} }}, "
+                   "json.dump({{'purelib': {purelib!r}, 'scripts': {scripts!r}, 'data': {data!r} }}, "
                    "sys.stdout)"
                   ).format(python=sys.executable,
                            purelib=str(self.tmpdir / 'site-packages2'),
-                           scripts=str(self.tmpdir / 'scripts2'))
+                           scripts=str(self.tmpdir / 'scripts2'),
+                           data=str(self.tmpdir / 'data'),
+                  )
 
         with MockCommand('mock_python', content=script1):
             ins = Installer.from_ini_path(samples_dir / 'package1' / 'pyproject.toml', python='mock_python',
@@ -288,6 +292,23 @@ def test_extras_error(self):
             Installer.from_ini_path(samples_dir / 'requires-requests.toml',
                             user=False, deps='none', extras='dev')
 
+    def test_install_data_dir(self):
+        Installer.from_ini_path(
+            core_samples_dir / 'with_data_dir' / 'pyproject.toml',
+        ).install_directly()
+        assert_isfile(self.tmpdir / 'site-packages' / 'module1.py')
+        assert_isfile(self.tmpdir / 'data' / 'share' / 'man' / 'man1' / 'foo.1')
+
+    def test_symlink_data_dir(self):
+        Installer.from_ini_path(
+            core_samples_dir / 'with_data_dir' / 'pyproject.toml', symlink=True
+        ).install_directly()
+        assert_isfile(self.tmpdir / 'site-packages' / 'module1.py')
+        assert_islink(
+            self.tmpdir / 'data' / 'share' / 'man' / 'man1' / 'foo.1',
+            to=core_samples_dir / 'with_data_dir' / 'data' / 'share' / 'man' / 'man1' / 'foo.1'
+        )
+
 @pytest.mark.parametrize(('deps', 'extras', 'installed'), [
     ('none', [], set()),
     ('develop', [], {'pytest ;', 'toml ;'}),

From 23efb36d7d6ea33c2ea0916ffa816e7e9db01562 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Sat, 15 Jan 2022 15:54:34 +0000
Subject: [PATCH 07/21] Document external data files

---
 doc/pyproject_toml.rst | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/doc/pyproject_toml.rst b/doc/pyproject_toml.rst
index 6ef305ab..c88d328d 100644
--- a/doc/pyproject_toml.rst
+++ b/doc/pyproject_toml.rst
@@ -417,4 +417,35 @@ These paths:
 
 Exclusions have priority over inclusions.
 
+External data section
+---------------------
+
+Data files which your code will use should go inside the Python package folder.
+Flit will package these with no special configuration.
+
+However, sometimes it's useful to package external files for system integration,
+such as man pages or files defining a Jupyter extension. To do this, arrange
+the files within a directory such as ``data``, next to your ``pyproject.toml``
+file, and add a section like this:
+
+.. code-block:: toml
+
+    [tool.flit.external-data]
+    directory = "data"
+
+Paths within this directory are typically installed to corresponding paths under
+a prefix (such as a virtualenv directory). E.g. you might save a man page for a
+script as ``(data)/share/man/man1/foo.1``.
+
+Whether these files are detected by the systems they're meant to integrate with
+depends on how your package is installed and how those systems are configured.
+For instance, installing in a virtualenv usually doesn't affect anything outside
+that environment. Don't rely on these files being picked up unless you have
+close control of how the package will be installed.
+
+.. note::
+
+   For users coming from setuptools: external data corresponds to setuptools'
+   ``data_files`` parameter, although setuptools offers more flexibility.
+
 .. _environment marker: https://www.python.org/dev/peps/pep-0508/#environment-markers

From c68295c766d9ed2dec267e8666a3f0b6b35aa95c Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Sat, 15 Jan 2022 15:58:55 +0000
Subject: [PATCH 08/21] Skip symlink test on Windows

---
 tests/test_install.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tests/test_install.py b/tests/test_install.py
index 70007e85..b4e9068e 100644
--- a/tests/test_install.py
+++ b/tests/test_install.py
@@ -300,6 +300,8 @@ def test_install_data_dir(self):
         assert_isfile(self.tmpdir / 'data' / 'share' / 'man' / 'man1' / 'foo.1')
 
     def test_symlink_data_dir(self):
+        if os.name == 'nt':
+            raise SkipTest("symlink")
         Installer.from_ini_path(
             core_samples_dir / 'with_data_dir' / 'pyproject.toml', symlink=True
         ).install_directly()

From 38a5aa714a3a9b9d2871a644d330c6d34fa087a3 Mon Sep 17 00:00:00 2001
From: BubuOT <97530794+BubuOT@users.noreply.github.com>
Date: Thu, 20 Jan 2022 12:49:25 +0100
Subject: [PATCH 09/21] docs: mention flit-core sdist behaviour

Ref: https://github.com/pypa/flit/issues/513#issuecomment-1017407065
---
 doc/pyproject_toml.rst | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/doc/pyproject_toml.rst b/doc/pyproject_toml.rst
index 6ef305ab..13296d8f 100644
--- a/doc/pyproject_toml.rst
+++ b/doc/pyproject_toml.rst
@@ -417,4 +417,13 @@ These paths:
 
 Exclusions have priority over inclusions.
 
+.. note::
+
+   If you are not using :ref:`build_cmd` but  ``flit_core`` via another build
+   frontend Flit doesn't doesn't check the VCS for files to include but instead
+   builds a 'minimal' sdist (which includes the files necessary to build a wheel).
+   You'll have to adaopt your inclusion/exclusion rules to achieve the same result
+   as you'd get with :ref:`build_cmd`.
+
+
 .. _environment marker: https://www.python.org/dev/peps/pep-0508/#environment-markers

From da5fc0afbf6cf8ba522444413eaf4abac6a7eb01 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <takowl@gmail.com>
Date: Thu, 20 Jan 2022 19:29:24 +0000
Subject: [PATCH 10/21] Spelling and punctuation fixes

---
 doc/pyproject_toml.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/doc/pyproject_toml.rst b/doc/pyproject_toml.rst
index 13296d8f..4e1392ef 100644
--- a/doc/pyproject_toml.rst
+++ b/doc/pyproject_toml.rst
@@ -420,9 +420,9 @@ Exclusions have priority over inclusions.
 .. note::
 
    If you are not using :ref:`build_cmd` but  ``flit_core`` via another build
-   frontend Flit doesn't doesn't check the VCS for files to include but instead
+   frontend, Flit doesn't doesn't check the VCS for files to include but instead
    builds a 'minimal' sdist (which includes the files necessary to build a wheel).
-   You'll have to adaopt your inclusion/exclusion rules to achieve the same result
+   You'll have to adapt your inclusion/exclusion rules to achieve the same result
    as you'd get with :ref:`build_cmd`.
 
 

From e3a9500ebf3c5905511efee376008d009f80c147 Mon Sep 17 00:00:00 2001
From: James Hilliard <james.hilliard1@gmail.com>
Date: Sat, 15 Jan 2022 18:15:05 -0700
Subject: [PATCH 11/21] Add bootstrap script/wheel module for flit_core

---
 flit_core/bootstrap.py       | 87 ++++++++++++++++++++++++++++++++++++
 flit_core/flit_core/wheel.py | 39 ++++++++++++++++
 flit_core/pyproject.toml     |  3 ++
 3 files changed, 129 insertions(+)
 create mode 100644 flit_core/bootstrap.py

diff --git a/flit_core/bootstrap.py b/flit_core/bootstrap.py
new file mode 100644
index 00000000..830a127f
--- /dev/null
+++ b/flit_core/bootstrap.py
@@ -0,0 +1,87 @@
+"""Install flit_core without using any other tools.
+
+Normally, you would install flit_core with pip like any other Python package.
+This script is meant to help with 'bootstrapping' other packaging
+systems, where you may need flit_core to build other packaging tools.
+
+Pass a path to the site-packages directory or equivalent where the package
+should be placed. If omitted, this defaults to the site-packages directory
+of the Python running the script.
+"""
+import argparse
+import sys
+import sysconfig
+from pathlib import Path
+from tempfile import TemporaryDirectory
+from zipfile import ZipFile
+
+from flit_core.wheel import add_wheel_arguments, build_flit_wheel
+
+srcdir = Path(__file__).parent.resolve()
+
+def extract_wheel(whl_path, dest):
+    print("Installing to", dest.resolve())
+    with ZipFile(whl_path) as zf:
+        zf.extractall(dest)
+
+def add_install_arguments(parser):
+    parser.add_argument(
+        '--wheeldir',
+        '-w',
+        type=str,
+        help=f'wheel dist directory (defaults to {srcdir.joinpath("dist").resolve()})',
+    )
+    purelib = Path(sysconfig.get_path('purelib'))
+    parser.add_argument(
+        '--installdir',
+        '-i',
+        type=Path,
+        default=purelib,
+        help=f'installdir directory (defaults to {purelib.resolve()}',
+    )
+    return parser
+
+def get_dist_wheel(wheeldir):
+    wheel_path = Path(wheeldir) if wheeldir is not None else srcdir.joinpath('dist')
+    wheel_glob = wheel_path.glob('flit_core-*.whl')
+    return next(wheel_glob, None)
+
+def build(args):
+    print("Building wheel")
+    outdir = srcdir.joinpath('dist') if args.outdir is None else Path(args.outdir)
+    whl_fname = build_flit_wheel(srcdir, outdir)
+    print("Wheel built", outdir.joinpath(whl_fname).resolve())
+
+def install(args):
+    dist_wheel = get_dist_wheel(args.wheeldir)
+
+    # User asked to install wheel but none was found
+    if dist_wheel is None and args.wheeldir is not None:
+        print(f"No wheel found in {Path(args.wheeldir).resolve()}")
+        sys.exit(1)
+
+    if dist_wheel is not None:
+        print("Installing from wheel", dist_wheel.resolve())
+        # Extract the prebuilt wheel
+        extract_wheel(dist_wheel, args.installdir)
+    else:
+        # No prebuilt wheel found, build in temp dir
+        with TemporaryDirectory(prefix='flit_core-bootstrap-') as td:
+            whl_fname = build_flit_wheel(srcdir, Path(td))
+            whl_path = Path(td).joinpath(whl_fname)
+            extract_wheel(whl_path, args.installdir)
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    subparsers = parser.add_subparsers()
+
+    build_parser = subparsers.add_parser('build')
+    build_parser = add_wheel_arguments(build_parser, srcdir)
+    build_parser.set_defaults(func=build)
+
+    install_parser = subparsers.add_parser('install')
+    install_parser = add_install_arguments(install_parser)
+    install_parser.set_defaults(func=install)
+
+    args = parser.parse_args()
+    args.func(args)
diff --git a/flit_core/flit_core/wheel.py b/flit_core/flit_core/wheel.py
index 8c87451e..d9f83a83 100644
--- a/flit_core/flit_core/wheel.py
+++ b/flit_core/flit_core/wheel.py
@@ -1,3 +1,4 @@
+import argparse
 from base64 import urlsafe_b64encode
 import contextlib
 from datetime import datetime
@@ -8,6 +9,7 @@
 import os.path as osp
 import stat
 import tempfile
+from pathlib import Path
 from types import SimpleNamespace
 from typing import Optional
 import zipfile
@@ -215,3 +217,40 @@ def make_wheel_in(ini_path, wheel_directory, editable=False):
 
     log.info("Built wheel: %s", wheel_path)
     return SimpleNamespace(builder=wb, file=wheel_path)
+
+def add_wheel_arguments(parser, srcdir=None):
+    if srcdir is None:
+        srcdir = Path.cwd()
+        parser.add_argument(
+            '--srcdir',
+            '-s',
+            type=Path,
+            default=Path.cwd(),
+            help='source directory (defaults to current directory)',
+        )
+
+    parser.add_argument(
+        '--outdir',
+        '-o',
+        type=Path,
+        default=srcdir.joinpath('dist'),
+        help=f'output directory (defaults to {srcdir.joinpath("dist").resolve()})',
+    )
+    return parser
+
+def build_flit_wheel(srcdir, outdir):
+    """Builds a wheel, places it in outdir"""
+    pyproj_toml = Path(srcdir).joinpath('pyproject.toml')
+    outdir.mkdir(parents=True, exist_ok=True)
+    info = make_wheel_in(pyproj_toml, Path(outdir))
+    return info.file.name
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser = add_wheel_arguments(parser)
+    args = parser.parse_args()
+    srcdir = Path.cwd() if args.srcdir is None else Path(args.srcdir)
+    outdir = args.outdir
+    print("Building wheel")
+    whl_fname = build_flit_wheel(srcdir, outdir)
+    print("Wheel built", outdir.joinpath(whl_fname).resolve())
diff --git a/flit_core/pyproject.toml b/flit_core/pyproject.toml
index ca3f46b2..03771248 100644
--- a/flit_core/pyproject.toml
+++ b/flit_core/pyproject.toml
@@ -19,3 +19,6 @@ dynamic = ["version"]
 
 [project.urls]
 Source = "https://github.com/pypa/flit"
+
+[tool.flit.sdist]
+include = ["bootstrap.py"]

From cfac2b923b992d4c07b8e71cb029ed97126e2c31 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Wed, 16 Feb 2022 11:53:50 +0000
Subject: [PATCH 12/21] Simplify bootstrap code

---
 flit_core/bootstrap.py       | 74 +++++++-----------------------------
 flit_core/flit_core/wheel.py | 46 +++++++++-------------
 2 files changed, 32 insertions(+), 88 deletions(-)

diff --git a/flit_core/bootstrap.py b/flit_core/bootstrap.py
index 830a127f..2c6c3d80 100644
--- a/flit_core/bootstrap.py
+++ b/flit_core/bootstrap.py
@@ -3,85 +3,39 @@
 Normally, you would install flit_core with pip like any other Python package.
 This script is meant to help with 'bootstrapping' other packaging
 systems, where you may need flit_core to build other packaging tools.
-
-Pass a path to the site-packages directory or equivalent where the package
-should be placed. If omitted, this defaults to the site-packages directory
-of the Python running the script.
 """
 import argparse
 import sys
 import sysconfig
 from pathlib import Path
-from tempfile import TemporaryDirectory
 from zipfile import ZipFile
 
-from flit_core.wheel import add_wheel_arguments, build_flit_wheel
-
-srcdir = Path(__file__).parent.resolve()
-
 def extract_wheel(whl_path, dest):
-    print("Installing to", dest.resolve())
+    print("Installing to", dest)
     with ZipFile(whl_path) as zf:
         zf.extractall(dest)
 
-def add_install_arguments(parser):
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
     parser.add_argument(
-        '--wheeldir',
-        '-w',
-        type=str,
-        help=f'wheel dist directory (defaults to {srcdir.joinpath("dist").resolve()})',
+        'wheel',
+        type=Path,
+        help=f'flit_core wheel to install (.whl file)',
     )
-    purelib = Path(sysconfig.get_path('purelib'))
+    purelib = Path(sysconfig.get_path('purelib')).resolve()
     parser.add_argument(
         '--installdir',
         '-i',
         type=Path,
         default=purelib,
-        help=f'installdir directory (defaults to {purelib.resolve()}',
+        help=f'installdir directory (defaults to {purelib})',
     )
-    return parser
-
-def get_dist_wheel(wheeldir):
-    wheel_path = Path(wheeldir) if wheeldir is not None else srcdir.joinpath('dist')
-    wheel_glob = wheel_path.glob('flit_core-*.whl')
-    return next(wheel_glob, None)
-
-def build(args):
-    print("Building wheel")
-    outdir = srcdir.joinpath('dist') if args.outdir is None else Path(args.outdir)
-    whl_fname = build_flit_wheel(srcdir, outdir)
-    print("Wheel built", outdir.joinpath(whl_fname).resolve())
 
-def install(args):
-    dist_wheel = get_dist_wheel(args.wheeldir)
-
-    # User asked to install wheel but none was found
-    if dist_wheel is None and args.wheeldir is not None:
-        print(f"No wheel found in {Path(args.wheeldir).resolve()}")
-        sys.exit(1)
-
-    if dist_wheel is not None:
-        print("Installing from wheel", dist_wheel.resolve())
-        # Extract the prebuilt wheel
-        extract_wheel(dist_wheel, args.installdir)
-    else:
-        # No prebuilt wheel found, build in temp dir
-        with TemporaryDirectory(prefix='flit_core-bootstrap-') as td:
-            whl_fname = build_flit_wheel(srcdir, Path(td))
-            whl_path = Path(td).joinpath(whl_fname)
-            extract_wheel(whl_path, args.installdir)
-
-if __name__ == "__main__":
-    parser = argparse.ArgumentParser()
-    subparsers = parser.add_subparsers()
-
-    build_parser = subparsers.add_parser('build')
-    build_parser = add_wheel_arguments(build_parser, srcdir)
-    build_parser.set_defaults(func=build)
+    args = parser.parse_args()
 
-    install_parser = subparsers.add_parser('install')
-    install_parser = add_install_arguments(install_parser)
-    install_parser.set_defaults(func=install)
+    if not args.wheel.name.startswith('flit_core-'):
+        sys.exit("Use this script only for flit_core wheels")
+    if not args.installdir.is_dir():
+        sys.exit(f"{args.installdir} is not a directory")
 
-    args = parser.parse_args()
-    args.func(args)
+    extract_wheel(args.wheel, args.installdir)
diff --git a/flit_core/flit_core/wheel.py b/flit_core/flit_core/wheel.py
index d9f83a83..df228ecd 100644
--- a/flit_core/flit_core/wheel.py
+++ b/flit_core/flit_core/wheel.py
@@ -218,39 +218,29 @@ def make_wheel_in(ini_path, wheel_directory, editable=False):
     log.info("Built wheel: %s", wheel_path)
     return SimpleNamespace(builder=wb, file=wheel_path)
 
-def add_wheel_arguments(parser, srcdir=None):
-    if srcdir is None:
-        srcdir = Path.cwd()
-        parser.add_argument(
-            '--srcdir',
-            '-s',
-            type=Path,
-            default=Path.cwd(),
-            help='source directory (defaults to current directory)',
-        )
 
+def main():
+    parser = argparse.ArgumentParser()
     parser.add_argument(
-        '--outdir',
-        '-o',
+        'srcdir',
         type=Path,
-        default=srcdir.joinpath('dist'),
-        help=f'output directory (defaults to {srcdir.joinpath("dist").resolve()})',
+        nargs='?',
+        default=Path.cwd(),
+        help='source directory (defaults to current directory)',
     )
-    return parser
 
-def build_flit_wheel(srcdir, outdir):
-    """Builds a wheel, places it in outdir"""
-    pyproj_toml = Path(srcdir).joinpath('pyproject.toml')
+    parser.add_argument(
+        '--outdir',
+        '-o',
+        help='output directory (defaults to {srcdir}/dist)',
+    )
+    args = parser.parse_args()
+    outdir = args.srcdir / 'dist' if args.outdir is None else Path(args.outdir)
+    print("Building wheel from", args.srcdir)
+    pyproj_toml = args.srcdir / 'pyproject.toml'
     outdir.mkdir(parents=True, exist_ok=True)
-    info = make_wheel_in(pyproj_toml, Path(outdir))
-    return info.file.name
+    info = make_wheel_in(pyproj_toml, outdir)
+    print("Wheel built", outdir / info.file.name)
 
 if __name__ == "__main__":
-    parser = argparse.ArgumentParser()
-    parser = add_wheel_arguments(parser)
-    args = parser.parse_args()
-    srcdir = Path.cwd() if args.srcdir is None else Path(args.srcdir)
-    outdir = args.outdir
-    print("Building wheel")
-    whl_fname = build_flit_wheel(srcdir, outdir)
-    print("Wheel built", outdir.joinpath(whl_fname).resolve())
+    main()

From 9a403a8c891a8defa96af348a297debcd2966d30 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Wed, 16 Feb 2022 11:58:04 +0000
Subject: [PATCH 13/21] Rename script to bootstrap_install.py

---
 flit_core/{bootstrap.py => bootstrap_install.py} | 7 +++++++
 flit_core/pyproject.toml                         | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)
 rename flit_core/{bootstrap.py => bootstrap_install.py} (82%)

diff --git a/flit_core/bootstrap.py b/flit_core/bootstrap_install.py
similarity index 82%
rename from flit_core/bootstrap.py
rename to flit_core/bootstrap_install.py
index 2c6c3d80..e04a007e 100644
--- a/flit_core/bootstrap.py
+++ b/flit_core/bootstrap_install.py
@@ -3,6 +3,13 @@
 Normally, you would install flit_core with pip like any other Python package.
 This script is meant to help with 'bootstrapping' other packaging
 systems, where you may need flit_core to build other packaging tools.
+
+Use 'python -m flit_core.wheel' to make a wheel, then:
+
+    python bootstrap_install.py flit_core-3.6.0-py3-none-any.whl
+
+To install for something other than the Python running the script, pass a
+site-packages or equivalent directory with the --installdir option.
 """
 import argparse
 import sys
diff --git a/flit_core/pyproject.toml b/flit_core/pyproject.toml
index 03771248..3652f9a3 100644
--- a/flit_core/pyproject.toml
+++ b/flit_core/pyproject.toml
@@ -21,4 +21,4 @@ dynamic = ["version"]
 Source = "https://github.com/pypa/flit"
 
 [tool.flit.sdist]
-include = ["bootstrap.py"]
+include = ["bootstrap_install.py", "build_dists.py"]

From 17df326a26b2b6466e8b8aa4789e5d8e22579757 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Wed, 16 Feb 2022 12:03:45 +0000
Subject: [PATCH 14/21] Add test for python -m flit_core.wheel

---
 flit_core/flit_core/tests/test_wheel.py | 11 ++++++++++-
 flit_core/flit_core/wheel.py            |  4 ++--
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/flit_core/flit_core/tests/test_wheel.py b/flit_core/flit_core/tests/test_wheel.py
index 9bb38fb2..882ae66a 100644
--- a/flit_core/flit_core/tests/test_wheel.py
+++ b/flit_core/flit_core/tests/test_wheel.py
@@ -3,7 +3,7 @@
 
 from testpath import assert_isfile
 
-from flit_core.wheel import make_wheel_in
+from flit_core.wheel import make_wheel_in, main
 
 samples_dir = Path(__file__).parent / 'samples'
 
@@ -29,3 +29,12 @@ def test_zero_timestamp(tmp_path, monkeypatch):
     # Minimum value for zip timestamps is 1980-1-1
     with ZipFile(info.file, 'r') as zf:
         assert zf.getinfo('module1a.py').date_time == (1980, 1, 1, 0, 0, 0)
+
+
+def test_main(tmp_path):
+    main(['--outdir', str(tmp_path), str(samples_dir / 'pep621')])
+    wheels = list(tmp_path.glob('*.whl'))
+    assert len(wheels) == 1
+    # Minimum value for zip timestamps is 1980-1-1
+    with ZipFile(wheels[0], 'r') as zf:
+        assert 'module1a.py' in zf.namelist()
diff --git a/flit_core/flit_core/wheel.py b/flit_core/flit_core/wheel.py
index df228ecd..8c3150ab 100644
--- a/flit_core/flit_core/wheel.py
+++ b/flit_core/flit_core/wheel.py
@@ -219,7 +219,7 @@ def make_wheel_in(ini_path, wheel_directory, editable=False):
     return SimpleNamespace(builder=wb, file=wheel_path)
 
 
-def main():
+def main(argv=None):
     parser = argparse.ArgumentParser()
     parser.add_argument(
         'srcdir',
@@ -234,7 +234,7 @@ def main():
         '-o',
         help='output directory (defaults to {srcdir}/dist)',
     )
-    args = parser.parse_args()
+    args = parser.parse_args(argv)
     outdir = args.srcdir / 'dist' if args.outdir is None else Path(args.outdir)
     print("Building wheel from", args.srcdir)
     pyproj_toml = args.srcdir / 'pyproject.toml'

From 6b5d64439bb299fc4875b7a7179c1fb613320800 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Thu, 17 Feb 2022 15:35:03 +0000
Subject: [PATCH 15/21] Update bootstrapping doc

---
 doc/bootstrap.rst | 33 +++++++++++++++++++--------------
 1 file changed, 19 insertions(+), 14 deletions(-)

diff --git a/doc/bootstrap.rst b/doc/bootstrap.rst
index 02da8945..19d7d923 100644
--- a/doc/bootstrap.rst
+++ b/doc/bootstrap.rst
@@ -13,24 +13,29 @@ from source?
 
 The key piece is ``flit_core``. This is a package which can build itself using
 nothing except Python and the standard library. From an unpacked source archive,
-you can run ``python build_dists.py``, of which the crucial part is::
+you can make a wheel by running::
 
-    from flit_core import buildapi
-    whl_fname = buildapi.build_wheel('dist/')
-    print(os.path.join('dist', whl_fname))
+    python -m flit_core.wheel
 
-This produces a ``.whl`` wheel file, which you can unzip into your
-``site-packages`` folder (or equivalent) to make ``flit_core`` available for
-building other packages. (You could also just copy ``flit_core`` from the
-source directory, but without the ``.dist-info`` folder, tools like pip won't
-know that it's installed.)
+And then you can install this wheel with the ``bootstrap_install.py`` script
+included in the sdist (or by unzipping it to the correct directory)::
+
+    # Install to site-packages for this Python:
+    python bootstrap_install.py dist/flit_core-*.whl
+
+    # Install somewhere else:
+    python bootstrap_install.py --installdir /path/to/site-packages dist/flit_core-*.whl
 
 As of version 3.6, flit_core bundles the ``tomli`` TOML parser, to avoid a
 dependency cycle. If you need to unbundle it, you will need to special-case
 installing flit_core and/or tomli to get around that cycle.
 
-I recommend that you get the `build <https://pypi.org/project/build/>`_ and
-`installer <https://pypi.org/project/installer/>`_ packages (and their
-dependencies) installed as the goal of the bootstrapping phase. These tools
-together can be used to install any other Python packages: ``build`` to create
-wheels and ``installer`` to install them.
+After ``flit_core``, I recommend that you get `installer
+<https://pypi.org/project/installer/>`_ set up. You can use
+``python -m flit_core.wheel`` again to make a wheel, and then use installer
+itself (from the source directory) to install it.
+
+After that, you probably want to get `build <https://pypi.org/project/build/>`_
+and its dependencies installed as the goal of the bootstrapping phase. You can
+then use ``build`` to create wheels of any other Python packages, and
+``installer`` to install them.

From ede1253e302fd5fbaa21bbbb4d85fc4c65900000 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Thu, 17 Feb 2022 16:06:35 +0000
Subject: [PATCH 16/21] Improve docs around external data

---
 doc/pyproject_toml.rst | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/doc/pyproject_toml.rst b/doc/pyproject_toml.rst
index 88fee376..8c56bdcf 100644
--- a/doc/pyproject_toml.rst
+++ b/doc/pyproject_toml.rst
@@ -428,6 +428,8 @@ Exclusions have priority over inclusions.
 External data section
 ---------------------
 
+.. versionadded:: 3.7
+
 Data files which your code will use should go inside the Python package folder.
 Flit will package these with no special configuration.
 
@@ -451,6 +453,11 @@ For instance, installing in a virtualenv usually doesn't affect anything outside
 that environment. Don't rely on these files being picked up unless you have
 close control of how the package will be installed.
 
+If you install a package with ``flit install --symlink``, a symlink is made
+for each file in the external data directory. Otherwise (including development
+installs with ``pip install -e``), these files are copied to their destination,
+so changes here won't take effect until you reinstall the package.
+
 .. note::
 
    For users coming from setuptools: external data corresponds to setuptools'

From 84d266045b3353a948e9a666e397567e0cf6c32a Mon Sep 17 00:00:00 2001
From: Steven Silvester <steven.silvester@ieee.org>
Date: Fri, 18 Feb 2022 11:14:25 -0600
Subject: [PATCH 17/21] Add Concurrency Limit in CI

---
 .github/workflows/test.yml | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 16e902a1..f7ac0f6c 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -2,6 +2,13 @@ name: Test
 
 on: [push, pull_request]
 
+concurrency:
+  group: >-
+    ${{ github.workflow }}-
+    ${{ github.ref_type }}-
+    ${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
 jobs:
   test:
     runs-on: ${{ matrix.platform }}

From 8360b643ca679f3f470a95353708b4e347037d8b Mon Sep 17 00:00:00 2001
From: Steven Silvester <steven.silvester@ieee.org>
Date: Fri, 18 Feb 2022 13:23:39 -0600
Subject: [PATCH 18/21] ignore push events on other branchs

---
 .github/workflows/test.yml | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index f7ac0f6c..5fa946ba 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -1,6 +1,10 @@
 name: Test
 
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - main
+  pull_request:
 
 concurrency:
   group: >-

From 08ac42dd0c3223f9eecbefcdcc2e4b4b5d55708a Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Mon, 21 Feb 2022 18:46:33 +0000
Subject: [PATCH 19/21] Reword docstring for walk_data_dir about output format

---
 flit_core/flit_core/common.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/flit_core/flit_core/common.py b/flit_core/flit_core/common.py
index c039f332..edf95d87 100644
--- a/flit_core/flit_core/common.py
+++ b/flit_core/flit_core/common.py
@@ -421,8 +421,8 @@ def dist_info_name(distribution, version):
 def walk_data_dir(data_directory):
     """Iterate over the files in the given data directory.
 
-    Yields absolute paths - caller may want to make them relative.
-    Excludes any __pycache__ subdirectories.
+    Yields paths prefixed with data_directory - caller may want to make them
+    relative to that. Excludes any __pycache__ subdirectories.
     """
     if data_directory is None:
         return

From fed7a7e371df2299e341fb60d517f257be38ceb4 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Mon, 21 Feb 2022 19:04:56 +0000
Subject: [PATCH 20/21] Release notes for 3.7

---
 doc/history.rst        | 15 +++++++++++++++
 doc/pyproject_toml.rst |  2 ++
 2 files changed, 17 insertions(+)

diff --git a/doc/history.rst b/doc/history.rst
index e3e6a126..343cd163 100644
--- a/doc/history.rst
+++ b/doc/history.rst
@@ -1,6 +1,21 @@
 Release history
 ===============
 
+Version 3.7
+-----------
+
+- Support for :ref:`external data files <pyproject_toml_external_data>` such
+  as man pages or Jupyter extension support files (:ghpull:`510`).
+- Project names are now lowercase in wheel filenames and ``.dist-info`` folder
+  names, in line with the specifications (:ghpull:`498`).
+- Improved support for :doc:`bootstrapping <bootstrap>` a Python environment,
+  e.g. for downstream packagers (:ghpull:`511`). ``flit_core.wheel`` is usable
+  with ``python -m`` to create wheels before the `build <https://pypi.org/project/build/>`_
+  tool is available, and ``flit_core`` sdists also include a script to install
+  itself from a wheel before `installer <https://pypi.org/project/installer/>`_
+  is available.
+- Use newer importlib APIs, fixing some deprecation warnings (:ghpull:`499`).
+
 Version 3.6
 -----------
 
diff --git a/doc/pyproject_toml.rst b/doc/pyproject_toml.rst
index 8c56bdcf..388e41eb 100644
--- a/doc/pyproject_toml.rst
+++ b/doc/pyproject_toml.rst
@@ -425,6 +425,8 @@ Exclusions have priority over inclusions.
    You'll have to adapt your inclusion/exclusion rules to achieve the same result
    as you'd get with :ref:`build_cmd`.
 
+.. _pyproject_toml_external_data:
+
 External data section
 ---------------------
 

From bdafdfec7158ba3774a47f7ed3d03645854a0540 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Tue, 22 Feb 2022 11:16:24 +0000
Subject: [PATCH 21/21] =?UTF-8?q?Bump=20version:=203.6.0=20=E2=86=92=203.7?=
 =?UTF-8?q?.0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .bumpversion.cfg                | 2 +-
 doc/conf.py                     | 2 +-
 flit/__init__.py                | 2 +-
 flit_core/flit_core/__init__.py | 2 +-
 pyproject.toml                  | 4 ++--
 5 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/.bumpversion.cfg b/.bumpversion.cfg
index f8280ed8..3fb51ecf 100644
--- a/.bumpversion.cfg
+++ b/.bumpversion.cfg
@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 3.6.0
+current_version = 3.7.0
 commit = True
 tag = False
 
diff --git a/doc/conf.py b/doc/conf.py
index 2837ce50..364334dc 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -57,7 +57,7 @@
 # built documents.
 #
 # The short X.Y version.
-version = '3.6.0'
+version = '3.7.0'
 # The full version, including alpha/beta/rc tags.
 release = version #+ '.1'
 
diff --git a/flit/__init__.py b/flit/__init__.py
index 57f689ea..24b23553 100644
--- a/flit/__init__.py
+++ b/flit/__init__.py
@@ -12,7 +12,7 @@
 from .config import ConfigError
 from .log import enable_colourful_output
 
-__version__ = '3.6.0'
+__version__ = '3.7.0'
 
 log = logging.getLogger(__name__)
 
diff --git a/flit_core/flit_core/__init__.py b/flit_core/flit_core/__init__.py
index 0314577d..c227699a 100644
--- a/flit_core/flit_core/__init__.py
+++ b/flit_core/flit_core/__init__.py
@@ -4,4 +4,4 @@
 All the convenient development features live in the main 'flit' package.
 """
 
-__version__ = '3.6.0'
+__version__ = '3.7.0'
diff --git a/pyproject.toml b/pyproject.toml
index 64d14150..cb56b5c1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,5 +1,5 @@
 [build-system]
-requires = ["flit_core >=3.6.0,<4"]
+requires = ["flit_core >=3.7.0,<4"]
 build-backend = "flit_core.buildapi"
 
 [project]
@@ -8,7 +8,7 @@ authors = [
     {name = "Thomas Kluyver", email = "thomas@kluyver.me.uk"},
 ]
 dependencies = [
-    "flit_core >=3.6.0",
+    "flit_core >=3.7.0",
     "requests",
     "docutils",
     "tomli",